Improvement of Sinterability of Ba(Mg&lt;sub&gt;1/3&lt;/sub&gt;Ta&lt;sub&gt;2/3&lt;/sub&gt;)O&lt;sub&gt;3&lt;/sub&gt;-Powder Compacts by BaTa&lt;sub&gt;2&lt;/sub&gt; O&lt;sub&gt;6&lt;/sub&gt; Additions

Tochi, Kunio

doi:10.2109/jcersj.100.1464

Cited by 18 publications

(4 citation statements)

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“…1 These are vitally important requirements for a solid-state component to be used in key microwave devices such as filters and oscillators used in telecommunication industry. Among the Ba-based complex perovskites, Ba(Mg 1/3 Ta 2/3 )O 3 (BMT) has stimulated a surge of interest for its excellent dielectric properties in the X band (8)(9)(10)(11)(12) and is considered to be the archetypal high-Q DR material. 2 Galasso and Pyle 3 found that it crystallizes in a disordered cubic structure or in an ordered hexagonal structure.…”

Section: Introductionmentioning

confidence: 99%

“…It may be noted that the volatilization of MgO in Ba(Mg 1/3 Ta 2/3 )O 3 at high temperature leads 10 to the formation of secondary phases. Later on, Tochi 11 observed that the sinterability of BMT could be improved with the addition of the extra phase BaTa 2 O 6 that formed during calcination. It was also reported 12 that, among the three starting materials, the reactivity of MgO is inferior to BaCO 3 and Ta 2 O 5 .…”

Section: Introductionmentioning

confidence: 99%

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Effect of Nonstoichiometry on the Structure and Microwave Dielectric Properties of Ba(Mg_0.33Ta_0.67)O₃

et al. 2004

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The effect of a slight A- and B-site cation nonstoichiometry on the structure, densification, and microwave dielectric properties of Ba(Mg1/ 3Ta2/3)O3 (BMT) was investigated. Magnesium and barium nonstoichiometric compositions based on Ba(Mg0.33 - x Ta0.67)O3 [x = −0.015, −0.010, −0.005, 0.0, 0.005, 0.010, 0.015, 0.020, 0.025, and 0.030] and Ba1 - x (Mg0.33Ta0.67)O3 [x = −0.015, −0.010, −0.005, 0.0, 0.0025, 0.005, 0.0075, 0.010, 0.015, 0.020, 0.025, and 0.030] were prepared using the conventional solid-state ceramic route. The lattice distortion and cation ordering were determined using X-ray diffraction technique. The phase composition and surface morphology were studied by EDX and scanning electron microscopy techniques, respectively. The sintered samples were characterized in the microwave frequency range using the resonance technique. It is found that a slight barium or magnesium deficiency can improve density, microwave dielectric properties, and cation ordering, while the addition of excess ions deteriorated them. The improvement in microwave dielectric properties was more pronounced in barium nonstoichiometric samples. Microwave dielectric properties of Ba0.9925(Mg0.33Ta0.67)O3 [εr = 24.7, τf = 1.2 ppm/°C, Quxf = 152 580 GHz] and Ba(Mg0.3183Ta0.67)O3 [εr = 25.1, τf = 3.3 ppm/°C and Quxf = 120 500 GHz] were found to be better than stoichiometric BMT [εr = 24.2, τf = 8 ppm/°C and Quxf = 100 500 GHz]. Raman spectroscopy was employed to study the effects of nonstoichiometry and related lattice distortions in BMT ceramics on their vibrational modes. Raman results clearly showed the 1:2 ordered structures of these materials with all active modes assigned. The spectra showed variations in the normal modes as a function of the composition. Also secondary phases contributed to the changes in the Raman spectra observed in compounds with x ≥ 0.02.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Nonstoichiometry on the Structure and Microwave Dielectric Properties of Ba(Mg_0.33Ta_0.67)O₃

et al. 2004

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“…Many efforts had been investigated to improve the sinterability of Ba(Mg 1/3 Ta 2/3 )O 3 ceramics at lower temperatures [8,9]. Chen et al reported that Ba(Mg 1/3 Ta 2/3 )O 3 ceramics had a bulk density of 0.98 theoretical density, the value was obtained by adding NaF as sintering aid [8].…”

Section: Introductionmentioning

confidence: 99%

Microwave dielectric characteristics of (1−x)BaTi4O9–xBa(Mg1/3Ta2/3)O3 ceramics

Yang

Diao

Chung

et al. 2008

Journal of Alloys and Compounds

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“…A number of dielectric ceramics based on complex perovskite compounds with the general formula A(B1/3B~/3)O3 (A = Ba, Sr; B = Mg, Zn, and Ni; and B' = Nb, Ta) have been investigated for this purpose [1][2][3][4][5], and the Ba(Mgl/3Ta2/3)O 3 (BMT) ceramics are of special interest due to their ultralow dielectric loss and the temperature independence of their dielectric constant [1,6]. However, BMT powders created by conventional solid-state-reaction methods have very poor sinterabilities [7], and this has been a serious problem in the practical applications of the present ceramics..…”

Section: Introductionmentioning

confidence: 99%

Sinterability improvement of Ba(Mg1/3Ta2/3)O3 dielectric ceramics

Chen

Suzuki

Sato

1994

J Mater Sci: Mater Electron

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The sinterability of Ba(Mgl/3Ta2/3)O 3 ceramics synthesized by solid-state-reaction methods was investigated. The poor sinterability of the present ceramics was found to be primarily due to the presence of satellite secondary phases of BasTa4015 and Ba4Ta20 ~, and the nearly complete densification of Ba(Mgl/3Ta2/3)O 3 ceramics was accomplished successfully by controlling the phase constitution of the calcined powders. For this purpose, enhanced ballmilling processes were found to be extremely effective. Moreover, excellent microwave dielectric characteristics (~r = 24.5-24.7, Q = 26 000 at 9.8 G Hz, and -of = 1.7 p.p.m. °C-1 ) were attained in the dense Ba(Mgl/3Ta2/3)O 3 ceramics without additives.

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Improvement of Sinterability of Ba(Mg<sub>1/3</sub>Ta<sub>2/3</sub>)O<sub>3</sub>-Powder Compacts by BaTa<sub>2</sub> O<sub>6</sub> Additions

Cited by 18 publications

References 0 publications

Effect of Nonstoichiometry on the Structure and Microwave Dielectric Properties of Ba(Mg_0.33Ta_0.67)O₃

Effect of Nonstoichiometry on the Structure and Microwave Dielectric Properties of Ba(Mg_0.33Ta_0.67)O₃

Microwave dielectric characteristics of (1−x)BaTi4O9–xBa(Mg1/3Ta2/3)O3 ceramics

Sinterability improvement of Ba(Mg1/3Ta2/3)O3 dielectric ceramics

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Improvement of Sinterability of Ba(Mg<sub>1/3</sub>Ta<sub>2/3</sub>)O<sub>3</sub>-Powder Compacts by BaTa<sub>2</sub> O<sub>6</sub> Additions

Cited by 18 publications

References 0 publications

Effect of Nonstoichiometry on the Structure and Microwave Dielectric Properties of Ba(Mg0.33Ta0.67)O3

Effect of Nonstoichiometry on the Structure and Microwave Dielectric Properties of Ba(Mg0.33Ta0.67)O3

Microwave dielectric characteristics of (1−x)BaTi4O9–xBa(Mg1/3Ta2/3)O3 ceramics

Sinterability improvement of Ba(Mg1/3Ta2/3)O3 dielectric ceramics

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Effect of Nonstoichiometry on the Structure and Microwave Dielectric Properties of Ba(Mg_0.33Ta_0.67)O₃

Effect of Nonstoichiometry on the Structure and Microwave Dielectric Properties of Ba(Mg_0.33Ta_0.67)O₃